1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___MEMORY_ASSUME_ALIGNED_H 11 #define _LIBCPP___MEMORY_ASSUME_ALIGNED_H 12 13 #include <__assert> 14 #include <__config> 15 #include <__type_traits/is_constant_evaluated.h> 16 #include <cstddef> 17 #include <cstdint> 18 19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20 # pragma GCC system_header 21 #endif 22 23 _LIBCPP_BEGIN_NAMESPACE_STD 24 25 template <size_t _Np, class _Tp> 26 _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp* __assume_aligned(_Tp* __ptr) { 27 static_assert(_Np != 0 && (_Np & (_Np - 1)) == 0, "std::assume_aligned<N>(p) requires N to be a power of two"); 28 29 if (__libcpp_is_constant_evaluated()) { 30 (void)__builtin_assume_aligned(__ptr, _Np); 31 return __ptr; 32 } else { 33 _LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN( 34 reinterpret_cast<uintptr_t>(__ptr) % _Np == 0, "Alignment assumption is violated"); 35 return static_cast<_Tp*>(__builtin_assume_aligned(__ptr, _Np)); 36 } 37 } 38 39 #if _LIBCPP_STD_VER >= 20 40 41 template <size_t _Np, class _Tp> 42 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp* assume_aligned(_Tp* __ptr) { 43 return std::__assume_aligned<_Np>(__ptr); 44 } 45 46 #endif // _LIBCPP_STD_VER >= 20 47 48 _LIBCPP_END_NAMESPACE_STD 49 50 #endif // _LIBCPP___MEMORY_ASSUME_ALIGNED_H 51